diff --git a/internal/service/auto_config.go b/internal/service/auto_config.go
index ae31894..548f437 100644
--- a/internal/service/auto_config.go
+++ b/internal/service/auto_config.go
@@ -401,8 +401,15 @@ func (s *AutoConfigService) BuildPipeline(req AutoConfigRequest, deploy bool) (*
 
     // ---- 4. Create recognition units for each video source ----
     editor.Instances = editor.Instances[:0] // clear previous instances on re-deploy
+    usedNames := map[string]bool{}
     for _, srcName := range cleanSources {
         unitName := deriveSafeInstanceName(srcName)
+        // Ensure unique instance name in case different source names derive to the same unitName
+        baseName := unitName
+        for i := 1; usedNames[unitName]; i++ {
+            unitName = fmt.Sprintf("%s-%d", baseName, i)
+        }
+        usedNames[unitName] = true
         inst := ConfigProfileInstanceEditor{
             Name:           unitName,
             Template:       templateName,
diff --git a/internal/service/config_assets.go b/internal/service/config_assets.go
index a26df11..b3d3960 100644
--- a/internal/service/config_assets.go
+++ b/internal/service/config_assets.go
@@ -1230,13 +1230,13 @@ func (s *ConfigPreviewService) SaveDeviceAssignment(asset DeviceAssignmentAsset)
     for _, ref := range asset.RecognitionUnits {
         profileName, _, err := parseRecognitionUnitRef(ref)
         if err != nil {
-            continue
+            return err
         }
         if profileName != asset.ProfileName {
-            continue
+            return fmt.Errorf("all recognition units must belong to scene template %q", asset.ProfileName)
         }
         if _, ok := seen[ref]; ok {
-            continue // skip duplicates
+            return fmt.Errorf("duplicate recognition unit: %s", ref)
         }
         seen[ref] = struct{}{}
         deduped = append(deduped, ref)
diff --git a/safesightd-linux-arm64 b/safesightd-linux-arm64
index 323136f..0eb0212 100644
Binary files a/safesightd-linux-arm64 and b/safesightd-linux-arm64 differ